Kelsey BennettLady Gaga and her pal, music legend Tony Bennett, made a surprise appearance Monday at the Frank Sinatra School of the Arts in Astoria, Queens.

It was the last day of school for the 700 students, and Bennett, who founded the school, wanted to make sure to put in an appearance. He asked Gaga to join him, and together, they staged a master class for the kids, discussing jazz, the Great American Songbook and other topics. Gaga then performed the standard, "Every Time We Say Goodbye," while Bennett crooned "The Very Thought of You." The two, who will release a joint album later this year, then teamed up for a duet on "I Can't Give You Anything But Love," during which they slow danced.

"When I am with Tony I feel like I am 15 years old at home listening to Ella [Fitzgerald] and [John] Coltrane records," she told the students. "The way he sings is effortless and so prolific. It’s so liberating to be able to sing jazz, especially at this point in my career!"

Bennett returned the compliment, saying of Gaga, "She is so bright and intelligent and she has it. In jazz you either got it, the syncopation, the rhythm or you don't, and when I heard Gaga I said, 'She's got it!'"

The event concluded with student choirs singing Bennett's "Smile," and "Applause" by Gaga.